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Abstract

Background:

The prognostic importance of exercise-induced ventricular arrhythmia (EIVA) may be confounded by the presence of lower-risk idiopathic right ventricular outflow tract arrhythmias with left bundle-branch block (LBBB) morphology.

Objective:

To determine whether right bundle-branch block (RBBB)–morphology EIVA was associated with increased mortality.

Design:

Retrospective cohort.

Setting:

Academic medical center.

Patients:

585 unique patients with EIVA and 2340 patients without EIVA, matched by age, sex, and risk factor, who were referred for exercise testing in an academic medical center.

Measurements:

Deaths and ischemia and infarction found on perfusion scan.

Results:

During a mean follow-up of 24 months (SD, 13), 31 deaths occurred in the EIVA group compared with 43 deaths in the group without EIVA (5.3% vs. 1.8%; P < 0.001). Worse survival in patients with RBBB-morphology or multiple-morphology EIVA (6.9%) than in patients without EIVA caused this difference. Patients with LBBB-morphology EIVAs had a mortality rate (2.5%) similar to that of patients without EIVA (P = 0.93, log-rank test). Among patients without known atherosclerotic coronary artery disease, any RBBB-morphology EIVA was associated with death (hazard ratio, 2.73 [95% CI, 1.78 to 4.13]; P < 0.001), but LBBB-morphology EIVA was not (hazard ratio, 0.82 [CI, 0.18 to 2.04]; P = 0.72).

Limitations:

Not all LBBB-morphology EIVA can be dismissed, and not all RBBB-morphology EIVA is high risk. Further evaluation of patients for structural heart disease was clinically driven, not protocol-driven.

Conclusion:

Right bundle-branch block– or multiple-morphology EIVA is associated with increased mortality. Inclusion of patients with isolated LBBB-morphology EIVA, which often is idiopathic, may contribute to differences in the prognostic importance of EIVA in previous studies.